Electrical ignition system for internal-combustion engines.



e. HONOLD.

ELECTRICAL IGNITION SYSTEM FOR INTERNAL COMBUSTION ENGINES. APPLICATION FILED MAR. 25. I912.

1, 1 39, 121 Patnted May 11, 1915.

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II II II IIII II I I lIIIlIllII III I| ']I||||lliIIllllIllIIIIllfl WITNESSES: INVENTOR W fi/f/o flow/4 ATTORNEY-9 G. HONOLD.

ELECTRICAL IGNITION SYSTEM FOR INTERNAL COMBUSTION ENGINES. APPLICATION FILED MAR. 25, I912.

'1 ,139,121. Patented May 11, 1915.

3 SHEETS-SHEET 2.

I INVENTOR 'ATTO NEY I G.HONOLD.

ELECTRICAL IGNITION SYSTEM FOR INTERNAL COMBUSTION ENGINES. APPLICATTON FILED MAR.25;19I2.

Patented May 11, 1915.

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ATTORNEYS UNITED STATES PATENT OFFICE.

GOTTLOIB HONOLD, OF STUTTGART, GERMANY, ASSIGNOR TO THE FIRM OF ROBERT BOSCH, 0F STUTTGART, GERMANY.

ELECTRICAL IGNITION SYSTEM FOR INTERNAL-GOMBUSTION ENGINES.

Specification of Letters Patent. Patented lIay 11, 1915.

Application filed March 25, 1912. 7 Serial No. 685,945. r I

To all-whom it may concern! Be it known that I, GOTTLOB HoNoLn, engineer, a subject of the German Emperor, residing at 11-13 Hoppenlaustrasse, Stuttgart, Germany, have invented certain new and useful Improvements in Electrical Ignition Systems for Internal-Combustion Engines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same. i

The invention relates to electrical ignition systems for internal combustion engines, and particularly to systems of ignition, in which there is one current supply for service ignition during running, and a second current supply independent of the first for starting ignition.

It is generally recognized that service ignition during running of an internal combusion engine is performed better by an ignition machine driven from the engine than by a battery. A system having a single ignition machine is not, however, well suited to ignition during starting, because in those cases where the engine still retains in one or more of its cylinders a combustible mixture which has been partially compressed there as the engine came to rest it is not possible to take advantage of this situation and start the engine by ignition Without cranking;

and even in those cases where it is necessary to crank the engine to draw a combustible mixture into the. cylinder such an ignition system requires that the engine should be cranked violently, until the ignition machine is turned at practically its normal running speed, to produce an ignition spark. On the other hand itis not feasible to provide.

. an arrangement in which the single ignition machine can be turned independently of the engine shaft because the ignition machine must be positively connected in fixed and invariable relation to the engine shaft to assure timely service under all circumstances. A single battery ignition is not entirely satisfactory because the battery 1s not nearly so reliable as the ignition machine for service ignition, and because with a single battery it is necessary to extend the adjustment of the period of ignition over a comparatively large angle in order that the ignition may be sufliciently retarded during starting and suiiiciently advanced during running. These considerations have led to the adoption of ignition systems in which a service ignition machine is directly connected to the engine for running ignition, and a battery is used for starting ignition; Such a system has, however,,the disadvantage that the battery ignition has to be cut out by hand as soon as the service ignition begins, and the character of thespark is limited by the conble of rotating its shaft at a suflicient speed to produce such sparks. Such an ignition machine may be conveniently mounted upon the dash-board of a motor car within reach of the ch'aufieur, and will produce sparks only so long as it is driven by its independent driving means. With such an arrangement, it is possible, if a charge of combustiblemixture remains in one of the cylinders of the engine, to start the engine without cranking by actuating the driving means of the starting ignition machine, and such actuation may be continued, and the speed of drive increased until there is produced a sufficient spark for ignition even under unfavorable circumstances, and until the service ignition begins, whereupon the chauffeur will cease to operate the starting ignition machine and no further sparks wi 1 be produced thereby.

In order toprovide in such a system, for. ignition in those cases wherefcranking is necessary, the present invention contemplates adisengageable coupling between the engine shaft and the starting ignition machine; and in the preferred form ofthe' in vention this arrangement takes the form of a disengageable coupling between the starting crank and the ignition machine, so that crank and the ignition machine the actuachines, such as that which constitutes the jointinvention of this applicant and Messrs. Ball and Mumprecht and which is disclosed in United States Letters Patent N 0. 1,014,824, of Jan. 16th, 1912.

The preferred embodiment of the invention will be particularly described in conncction with the accompanying drawings in which-- Figure 1 shows in elevation and Fig. 2

in plan, the application of the invention to a four-cylinder engine; Figs. 3 and 4, are diagrams of circuit connections; Fig. 5 is a perspective view showing the starting ignition machine on the dash-board of a motor car, together with the connection between the ignition machine and the crank; Fig. 6 is a front elevation of the motor car showing said connection; Fig. 7 is a detail of the connection; and Fig. 8 is an elevation partly in section of the casing of the starting'ignition machine showing the disengageable coupling between the ignition machine and the crank, together with the independent driving means for the ignition machine.

In Figs. 1, 2, 3 and 4, a is the service ignition machine, which may be of any well known type, and is shown in this case as an ignition machine having a primary winding 6 and a secondary winding d. The interrupter a is operatively connected to the engine, while the brush f pressing on the slip ring e is electrically connected with an appropriate distributer contact. The source for starting ignition is the ignition machine z' with primary winding is, secondary winding m, interrupter Z, and slip ring n. The brush 0 for slip ring 71. is "electrically connected with an appropriate distributer contact. In Fig. 3 is shown a distribution system like that of the above-mentioned U. S. patent in which the brush is connected to the contact 9 of the distri uter h, and the brush 0 is connected to distributer contact p. The segments g g g and 9 of the distributer k are electrically connected with respective spark plugs 1, 2, 3 and 4, of the cylinders as shown. In Fig. 4 the secondary winding d is connected to the contact 9' of thedistributer h the segments of which are connected to one set of spark plugs 5, 6, 7 and 8, while the secondary winding m is connected to the contact p of a distributor b the segments of which are connected to a separate set of plugs 9, 10, 11 and 12. If

now the engine has been brought to rest by cutting off the service ignition, the four pistons will be substantially in the position shown in Fig. 1, and cylinders 13 and 14 will contain partly compressed combustible mixture capable of starting the engine upon ignition. Under such circumstances, the engine may be started by rapidly rotating the shaft of the starting ignition machine 5 by means of the hand-crank m or any other suitable means. The current produced in the secondary winding m is conducted to the distributer contact and thence to the spark plug of the cylinder 13, so that a spark 1s generated and the partly compressed combustible mixture in that cylinder is ignited, whereupon its piston is driven downward as indicated by the arrow. In this way the engine is set in motion and as soon as the speed has increased so that the service ignition machine a is rotated at sufliciently high speed the service ignition current is produced and the engine continues to rotate. If the rotation of the engine produced by the starting ignition in cylinder 13 is not sufficiently rapid to produce service ignition then the actuation of the starting ignition machine 11 must be continued, generating starting sparks in those cylinders with which the starting ignition machine is successively connected, until the service ignition begins. Thereupon the actuation of the starting ignition machine is discontinued and it produces no further sparks.

It will be observed that the arrangement of the distributors is such that when the engine is at rest the service ignition machine is connected with that distributer segment which corresponds to the spark plug of that cylinder which is in the compression stroke, while the starting ignition machine is connected to that distributer segment which corresponds to the spark plug of that cylinder which is in the expansion or working stroke. If now it is desired to start the engine when there'is 'no combustible mixture in any cylinder, it is necessary to provide a connection between the engine shaft and the starting ignition machine, and this is preferably effected by means of ,a disengageable connection between the crank and thestarting ignition machine. To this end the crank 1', which has the ordinary ratchet engagement with the engine shaft carries a sprocket wheel 1" which through the chain 0' drives a sprocket wheel 1' on the end of a flexible shaft incased in a protecting cover r and extending to the starting ignition machine within the casin s on the dash-board. The squared end If %see Fig. 8) of the flexible shaft enters a cup t rotatably mounted in the wall of the casing s and constituting one member of a saw-tooth coupling of ordinary form. The outer memher it of this coupling is splined on the shaft with a pinion (not shown) on the shaft of.

the ignition machine 2'. With this arrangement it is possible to actuate the starting ignition machine from the drivers seat without turning the crank of the engine since in that case the inclined teeth of the saw-tooth clutch slip over one another and permit the 'free rotation of the shaft :12 to turn the shaft of the ignition machine 71 at high speed. 0n the other hand, if it is necessary to crank the engine the turning of the crank r rotates the flexible shaft by way of the sprocket wheels 0* and r and the chain r and the rotation of the flexible shaft is imparted to the shaft of the ignition machine through the clutch'members t and t the shaft m and the pinion 'w.

Having'thus described my invention, what I claim is:

1. In an ignition system for internal combustion engines, the combination with a service ignition machine having a positive driving connection to the engine, of a handcrank for starting the engine, a starting ignition machine, and mechanism for efiecting a driving connection between the starting ignition machine and the en 'ne shaft during the cranking operation .su stantially as described.

2. In an ignition system'for internal combustion engines, the combination with a service ignition machine having a positive driving connection to the engine, of a hand- .crank for the engine having a ratchet engagement with the engine shaft, a starting ignition machine, and a driving connection between the crank and the starting ignition machine; substantially as described.

3. In an ignition system for internal combustion engines, the combination with a service ignition machine having a positive driving connection to the en e, of a handcrank for starting the englne, a starting ignition machine, mechanism for effecting a driving connection between'the starting ignition machine and the engine shaft during the cranking operation, said mechanism including a disengageable coupling, and independent driving means for the startin ignition machine; substantially as describe 4. In an ignition system for internal combustion engines, the combination with a service ignition machine having a positive driving connection to the engine, of a handcrank for the engine having a ratchet enagement with the engine shaft, a starting ignition machine, a disengageable driving connection between the crank and the starting ignition machine, and independent driving means for the starting ignition machine; substantially as describe In testimony whereof I have afiixed my signature, in presence of two witnesses.

GOTILOB HONOLD.

Witnesses:

MAX ANsoHU'rz, PAUL WOLFART. 

